Azpilicueta, 22, fills the gap in Chelsea's squad created by the decision to release Jose Bosingwa earlier this summer.

Marseille have confirmed the transfer on their official website, but there are no details as to the fee involved or the length of contract he has signed. Reports this week suggested the Blues were going to pay in the region of £7 million.

The defender played for Spain's Olympic team at the London Games - where they surprisingly exited at the group stage - after missing out on selection for Euro 2012.

He made 41 appearances for Marseille last season, including eight in the Champions League, and scored one goal.

Prior to joining Marseille, he was a regular at Osasuna for three seasons, shifting into the backline after beginning life as a midfielder.

His arrival continues Chelsea's summer spending spree, with Victor Moses and another striker expected to also make the move to Stamford Bridge before the transfer window closes on August 31.